Question: Express your answer as a mixed number simplified to lowest terms. $13\dfrac{4}{15}+8\dfrac{6}{9} = {?}$
Solution: Separate the whole numbers from the fractional parts: $= {13} + {\dfrac{4}{15}} + {8} + {\dfrac{6}{9}}$ Bring the whole numbers together and the fractions together: $= {13} + {8} + {\dfrac{4}{15}} + {\dfrac{6}{9}}$ Add the whole numbers: $=21 + {\dfrac{4}{15}} + {\dfrac{6}{9}}$ Simplify each fraction: $= 21 + {\dfrac{4}{15}} + {\dfrac{2}{3}}$ Find a common denominator for the fractions: $= 21+\dfrac{4}{15}+\dfrac{10}{15}$ Add the fractions: $= 21+\dfrac{14}{15}$ Combine the whole and fractional parts into a mixed number: $= 21\dfrac{14}{15}$